Integral helmets of this type have primarily been known in the form of so-called “flip-up helmets”. They comprise a chin part which extends over the entire chin region and is connected to the helmet shell on both sides thereof via pivot joints which each have a substantially horizontal pivot axis, with the result that the chin part performs a pivoting movement which corresponds to the pivoting movement of a visor panel that usually covers the visor opening. Such an integral helmet is disclosed, for example, in DE 28 46 636 A1.
DE 28 53 260 also discloses designing a central piece of the chin part such that it can swing at one side about a vertical axis, with the result that a chin part can be swung open in the central region of the chin region. The chin part is provided with two lateral extension pieces which can be connected in an overlapping manner to extension pieces of the helmet shell that project into the chin region. Locking is performed by vertically movable pins of the chin part that can engage vertically into corresponding blind holes in the extension pieces of the helmet shell. However, such a design of the chin region does not allow the required stability.
No objections can be raised from the safety point of view with regard to the customary flip-up helmets of the aforementioned type whose chin parts are mounted such that they can be pivoted up and over the visor opening. However, they do have a relatively high weight as a result of the fastening and locking means required for movably fastening the chin part to the helmet shell.